OFFSET
1,2
COMMENTS
Value is unique by this definition up to a(103) = 9900. To go beyond this number, we could define the sequence in terms of "smallest value of x*y" or "largest value of x*y". We choose smallest here.
EXAMPLE
a(5) = 4 * 5 = 20; sigma(20) = 42
CROSSREFS
KEYWORD
nonn
AUTHOR
Stewart Gordon, Sep 26 2011
STATUS
approved